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the ones in plastids. Chromatophoretargeted proteins are either small (less than 90 amino acids) and lack obvious targeting signals, or long (greater than 270 amino acids) and carry an unusual amino-terminal extension. This putative targeting signal differs from known organellar targeting signals: it is 200 amino acids long and conserved in sequence whereas amino-terminal transit peptides that target proteins to mitochondria and primary plastids are much shorter and show a typical amino acid composition and common physicochemical properties but no sequence conservation. One of the small chromatophore-targeted proteins (i.e. <90 amino acids, without discernible targeting signal) was observed by immunogold electron microscopy in the Golgi, suggesting that, differently from protein traffi cking into primary plastids, vesicular transport via the Golgi is involved in protein traffi cking into the chromatophore. And different from plastids, classical metabolite transporters are apparently missing in the inner chromatophore membrane despite the obvious need for extensive metabolite exchange. Are there other photosyntheticPaulinella species? Yes. After chromatophore integration, the photosynthetic Paulinella lineage diversifi ed and today contains, besides P. chromatophora, at least two additional species, namely P. micropora and P. longichromatophora. Cells of these three species differ slightly in morphology and at the molecular level. Furthermore, divergent evolution entailed approximately 40 independent losses of orthologous gene families between the chromatophore genome of P. chromatophora and each of the other two species. Why isn't Paulinella more widely studied?There are several features that render Paulinella a diffi cult model system. The cells grow very slowly (doubling time approximately 6-7 days), cannot be cryopreserved, clump together in liquid culture, and cannot grow on nutrient agar plates. Furthermore, the nuclear genome is exceedingly large and repetitive (the ~1 Gbp nuclear genomes of two P. micropora strains were recently sequenced; the nuclear genome of P. chromatophora was estimated to be 10 Gbp in size). These diffi culties have so far discouraged the development of molecular tools for Paulinella species. However, despite these diffi culties, the genus Paulinella has proven an incredibly valuable system to gain unprecedented insights into the evolution and physiology of earlystage photosynthetic organelles. Thus, we feel that the singularity of these organisms justifi es a signifi cant effort to unravel their biology and we hope that many researchers decide to join in this endeavor.Where can I fi nd out more? Bhattacharya, D., Helmchen, T., and Melkonian, M. (1995). Molecular evolutionary analyses of nuclear-encoded small-subunit ribosomal RNA identify an independent rhizopod lineage containing the Euglyphina and the Chlorarachniophyta.

When we produce actions we predict their likely consequences. Dominant models of action control suggest that these predictions are used to ‘cancel’ perceptual processing of expected outcomes. However, normative Bayesian models of sensory cognition developed outside of action propose that rather than being cancelled, expected sensory signals are represented with greater fidelity (sharpened). Here, we distinguished between these models in an fMRI experiment where participants executed hand actions (index vs little finger movement) while observing movements of an avatar hand. Consistent with the sharpening account, visual representations of hand movements (index vs little finger) could be read out more accurately when they were congruent with action and these decoding enhancements were accompanied by suppressed activity in voxels tuned away from, not towards, the expected stimulus. Therefore, inconsistent with dominant action control models, these data show that sensorimotor prediction sharpens expected sensory representations, facilitating veridical perception of action outcomes.

Bayesian theories of perception have traditionally cast the brain as an idealised scientist, refining predictions about the outside world based on evidence sampled by the senses. However, recent predictive coding models include predictions that are resistant to change, and these stubborn predictions can be usefully incorporated into cognitive models.

Models of action control suggest that predicted action outcomes are 'cancelled' from perception, allowing agents to devote resources to more behaviorally-relevant unexpected events. These models are supported by a range of findings demonstrating that expected consequences of action are perceived less intensely than unexpected events. A key assumption of these models is that the prediction is subtracted from the sensory input. This early subtraction allows preferential processing of unexpected events from the outset of movement, thereby promoting rapid initiation of corrective actions and updating of predictive models. We tested this assumption in three psychophysical experiments. Participants rated the intensity (brightness) of observed finger movements congruent or incongruent with their own movements at different timepoints after action. Across Experiments 1 and 2, evidence of cancellation -whereby congruent events appeared less bright than incongruent events -was only found 200 ms after action, whereas an opposite effect of brighter congruent percepts was observed in earlier time ranges (50 ms after action). Experiment 3 demonstrated that this interaction was not a result of response bias. These findings suggest that 'cancellation' may not be the rapid process assumed in the literature, and that perception of predicted action outcomes is initially 'facilitated'. We speculate that the representation of our environment may in fact be optimized via two opposing processes: The primary process facilitates perception of events consistent with predictions and thereby helps us to perceive what is more likely, but a later process aids the perception of any detected events generating prediction errors to assist model updating.

Words in body of text: 2434 (<2500). Acknowledgements:We are grateful to Kaat Alaerts for providing the original stimuli and much useful advice concerning their generation, as well as Nicholas Holmes for advice concerning the bootstrapping analysis. RE was funded by a graduate teaching assistantship from Birkbeck, University of London and DY was funded by an ESRC Studentship. JC is supported by the Birmingham Fellows programme. 2 AbstractOur movement kinematics provide useful cues about our affective states. Given that our experiences furnish models that help us to interpret our environment, and that a rich source of action experience comes from our own movements, the present study examined whether we use models of our own action kinematics to make judgments about the affective states of others. For example, relative to one's typical kinematics, anger is associated with fast movements. Therefore, the extent to which we perceive anger in others may be determined by the degree to which their movements are faster than our own typical movements. We related participants' walking kinematics in a neutral context to their judgments of the affective states conveyed by observed point-light walkers (PLWs). As predicted, we found a linear relationship between one's own walking kinematics and affective state judgments, such that faster participants rated slower emotions more intensely relative to their ratings for faster emotions. This relationship was absent when observing PLWs where differences in velocity between affective states were removed. These findings suggest that perception of affective states in others is predicted by one's own movement kinematics, with important implications for perception of, and interaction with, those who move differently.Keywords: Action perception; emotion; affective states; point-light walkers; expertise Public significance statement: The way that we move provides useful cues about our emotions. For example, we move more quickly than our average speed when we are feeling angry and more slowly when we are feeling sad. The present study shows that we make judgments about others' emotional expressions relative to how we move ourselves. To give an example, rather than everyone interpreting movements of a certain speed as angry, individuals may only think that others feel angry if these movements are faster than their own typical movement speed. Therefore, we are better placed to understand the emotions of others who tend to move more similarly to us. These findings have 3 important implications for our understanding of and interactions with clinical and cultural groups whose movements are dramatically different from our own. 4

Perceptual systems must rapidly generate accurate representations of the world from sensory inputs that are corrupted by internal and external noise. We can typically obtain more veridical representations by integrating information from multiple channels, but this integration can lead to biases when inputs are, in fact, not from the same source. While a considerable amount is known about how different sources of information are combined to influence what we perceive, it is not known whether temporal features are combined. It is vital to address this question given the divergent predictions made by different models of cue combination and time perception concerning the plausibility of crossmodal temporal integration, and the implications that such integration would have for research programmes in action control and social cognition. Here we present four experiments investigating the influence of movement duration on the perceived duration of an auditory tone. Participants either explicitly (Experiments 1-2) or implicitly (Experiments 3-4) produced hand movements of shorter or longer durations, while judging the duration of a concurrently presented tone (500-950 ms in duration). Across all experiments, judgments of tone duration were attracted towards the duration of executed movements (i.e., tones were perceived to be longer when executing a movement of longer duration). Our results demonstrate that temporal information associated with movement biases perceived auditory duration, placing important constraints on theories modelling cue integration for state estimation, as well as models of time perception, action control and social cognition.

▪ Abstract  In broad brush strokes, this essay identifies and reviews key trends and theoretical orientations that have shaped the field of educational ethnography from the period of its inception to the closing decade of the twentieth century. It demonstrates how the growth of educational ethnography as a subfield within anthropology reflects a growing focus on prescriptive, applied, and reformist research within urban contexts. It maps the transition from modernist formulations of the field in its formative days, when ethnographies laid claim to being sealed and scientific texts, to the more recent formulations shaped by postmodern and poststructural ideas that undermine earlier meanings of culture and call attention to the explanatory limits of ethnography. This review draws on examples from North America and Britain and makes no claim to being exhaustive of the vast and growing field. Although it delineates what distinguishes successive decades of educational ethnography, the essay argues for understanding the developments not as distinct phases but as overlapping moments in the evolution of the field of study. Attention is drawn to how developments in theory and method, in particular a move toward reflexivity in educational ethnography, mirror developments in the discipline of anthropology at large.